FMS was engaged to conduct a thorough assessment of a potentially serious EMI Threat to sensitive TEM/SEM Microscopes located in Imaging Suites immediately adjacent to a planned new research lab with two high field, 9 Tesla super conducting magnets. Several of the microscopes had stray field EMI stray field specifications of < 0.1 mG for optimum operation.

Fringe field conditions present in areas adjacent to the two 9 Tesla super conducting research magnets.

Computer simulations were generated to provide a view of fringe field conditions likely to be present in areas adjacent to the two 9 Tesla super conducting research magnets. The computer models indicated that fringe field magnitudes ranging from 1 to > 100 mG could be present in the adjacent Imaging Suites with the research magnets energized. As a consequence, all instruments planned for use in the adjacent Imaging Suites were confirmed to be at substantial EMI threat risk from operation of the 9T research magnets.

Robust passive shielding scheme reduced remaining fringe field

As a further and supplemental measure, a robust passive shielding scheme was developed by FMS to ensure that remaining fringe field levels from the two compensated research magnets were sufficiently reduced to eliminate EMI threat potential to adjacent TEM and SEM microscopes.

Before and after shielding plots of the two 9 Tesla super conducting research magnet’s fringe fields

Plots of the two 9 Tesla super conducting research magnets fringe fields prior to and after incorporation of full dipole compensation and use of passive shielding measures, demonstrate substantial reductions sufficient to ensure that operation of the research magnets will not present an EMI threat concern to TEM and SEM microscopes in adjacent Imaging Rooms.

FMS EXPERIENCE

Over its 20 years, FMS has successfully completed hundreds of EMI projects which included a diverse range of consulting and mitigation services.